Dojo 1.8 / AMD Style Gmaps Loader

gistfile1.js

/**
 * Dojo AMD Google Maps Loader Plugin
 */
define([
    "dojo/_base/kernel",
    "dojo/topic"
], function(kernel, topic) {

    var w = kernel.global;
    w._googleApiLoadCallback = function() {
        w.GMAPS_API_AVAILABLE = true;
        topic.publish("/google/maps/apiloaded", w.google.maps);
    };

    return {
        load: function(param, req, loadCallback) {
            if(w.GMAPS_API_AVAILABLE) {
                return w.google.maps;
            } else {
                topic.subscribe("/google/maps/apiloaded", loadCallback);
                require([FULL_PATH_TO_GMAPS_API], function() { /* Do nothing */ });
            }
        }
    };

});

Can you give me a sample of how to use it? (from a beginner point of view)

Here's a working example of a loader based on this one:
https://gist.github.com/ca0v/7450696